Could be true vs must be true: the LSAT's tightest distinction

On Must Be True questions the credited answer is guaranteed by the passage. Four others are consistent with it — nothing rules them out, they are entirely plausible, and none of them is established. That distinction, between possible and proven, is the entire question type.

Consistent is not the same as supported

The mistake is checking whether an answer CONFLICTS with the passage and, finding no conflict, treating it as supported. But most statements about any topic conflict with nothing. Absence of contradiction is a very low bar, and the trap answers all clear it.

The bar is that the passage FORCES it. Ask: could everything in the passage be true while this answer is false? If yes — even in one unlikely arrangement — it is not must be true. That is a harder question than "does this seem right", and it is the one being asked.

The reasonable-addition trap

The most attractive version adds a small, sensible step the passage never took. The text establishes a group has a property; the answer says the property is why the group formed. Plausible, probably true in the world, and one inference past the evidence.

Your own knowledge works against you here, which is why these questions punish expertise. Knowing a subject makes the extra step feel like part of the passage rather than an addition to it.

Modest answers win

Credited answers on this type are often underwhelming — narrow, hedged, close to restating a combination of two sentences. That is what "guaranteed" looks like. The more a statement claims, the more the passage has to establish, so the safest answers are usually the smallest.

If a choice feels like a genuine insight, be suspicious. Insight is generally a sign that something was added, and Must Be True does not reward adding.